One of the main reasons for massive inflation in germany following world war 1 was

There are multiple reasons for the massive inflation in Germany following the war. Some of these major reasons includes that Germany had to pay reparations (debt from war), as well as the fact they had to borrow money from other nations to feed their war. To compensate for all of this, the German government printed more money than they actually had, so this cause them to fall into debt. A little fact because of all of this; by 1923, the U.S. dollar was worth 4,210,500,000,000 or four trillion German marks. I hope this helped :) 

After the treaty of Versailles Germany was forced to pay the allies money for the war damages

It exists because it deals with human behavior and patterns, not in natural occurrences. For example, it overlaps with geography when it comes to things like migrations. Migrations are explained in geography in history due to events and land crossed and things like that, but sociology deals with reasons that the people had and statistics and things like their behavior.